Process of making hydrochinon



UNITED? STATES PATENT OFFICE.

HAROLD VON BRAMER, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OFNEW YORK.

PROCESS OF MAKING- HYDROCHINON.

No Drawing.

Monroe and State of New York, have in vented certain new and useful Improvements in Processes of Making Hydrochinon,

' of. which the following is a full, clear, and

exact specification.

This invention relates to the manufacture of hydrochinon and to the steps used in such process.

One object of the invention is to produce hydrochinon as inexpensively as possible from materials of small cost by means of steps which will give large ,yields. Other objects will hereinafter appean' I have discovered hat -a paradihalogenbenzol, preferably para-dichlorbenzol, ma be converted into hydrochinon by first su fonating'it and then re-acting on the sulfonated product 'to replace both halogen atoms with hydroxyl groups and to eliminate the sulfonating group. The sulfonation of the paradihalogenbenzol makes the halogen atoms susceptible to the action of bodies containing strongly re-active hydroxyl grou s, such as the hydroxids of the alkali meta In applying my discovery I have worked out useful auxiliary steps which facilitate the carrying out of my process on a commercialscale.

Since paradichlorbenzol is a relatively inexpensive by-product of certain, chemical processes, I shall give a detailed working example of my method as applied to it. But it is to be understood that my invention is not limited to these illustrative details. The first step is the sulfonatingope'ration, While stlrring vigorously and maintaining a temperature of from 130 to 140 C.-, I re-acton 100 parts of paradichlorbenzol with 200 parts of commercial'oleum. A purer fum- U mg sulfuric acid may bexusedior this sulfonation, but I prefer the commercial grade.

, The sulfonating reaction is often-completed in. about three-quarters of an hour. The

- result is considered to be the replacement of one of the h dro ens of the paradichlorben ml with a- 0 group.

' The solution is next poured into 300 parts of ice cold water. If the s'ulfonation is not completed, any unchanged paradichlorben-- zol can-be distilled out with steam, although 'peratures of from 175 to 200 C. are

Specification of Letters ,Patent. Patented J uly 4, 1922. Application iiled June 28, 1920. Serial No. 392,417. 1 i

the sulfonation is usually complete enou h to make this distillation unnecessary. o the solution is now added 7 5 parts of sodium chloride. A double decomposition takes. place, sodium paradichlorbenzolsulfonate being precipitated, and free hydrochloric acid remaining in the solution. To insure completion of the re-action, the solution may be stirred for say an hour. The precipitated sodium salt is filtered ofl, a suction filter' being convenient. I find that the yield is nearly quantitative. l

The sodium paradichlorbenzolsulfonate obtained by the preceding steps (when further purified if desired, although this is not usually necessary) is next converted into a hydrochinon body by treatment with an aqueous solution of a strong base. The sodium paradichlorbenzolsulfonateo obtained, as above explained, from the sulfonation of 100 parts of paradichlorbenzol is re-acted upon with 150,parts of'caustic soda in 225 parts of water. The mixture is put in any suitable apparatus for heating under pressure, a convenient one being an autoclave which can be made of either iron copper,

ough mixing, the autoclave is sealed and the heating operation performed until the sodium paradichlorbenzolsulfonate changes. into the sodium salt of hydrochinon. I find that stirring facilitates the conversion. Ten;-

pre erable, a yield of about half of'the theoretical amount of the hydrochinon body beingobtained if these. temperatures are maintained for twenty-four hours. The pressure in the autoclave, of course, varies automatically with the tem'peratureused.

After cooling, the solution is taken from the autoclave and the "remaining alkali is neutralized with any suitable acid, say hydrochloric, the latter being added until the solutionis slightly acid. Sodium sulfite is formed .in the, re-action and. one convenient way of determining the prop'er'degree of sulfur dioxide is apparent. After boiling --for a few minutes, the solution is then cooled and the hydrochinon extracted with. ether or any other suitable solvent in the well known ing the hydrochinon which can be furacidification is to notewhen the odor of a way. The solventfinally is distilled leavthe steps of sulfonating described my invention, what Having thus andfdesire to secure by Let- I claim as new ters Patent is:

1. In the process of converting a paradihalogenbenzol into hydrochinon, the steps of treating the paradihalogenbenzol with a sulfonating agent to replace a hydrogen in the paradihalogenbenzol with a sulfonating group andre-acting on the parad-ihaloge'm benzol -sulfonated compound thus produced with an agent furnishing strongly reactive hydroxyl groups to replace both halogens of such paradihalogenbenzolsulfonated compound with hydroxyl groups and-to remove the sulfonating group.

2. In theprocess of making hydrochinon, .paradichlorbenzol and re-aoting on the product thus obtained with an agent supplying strongly re-active hydroxyl groups to convert said product into a hydrochinon body.

3. In the process of making hydrochinon, the steps of acting on paradichlorbenzol with a sulfonating agent until paradichlorbenzolsulfonate is produced, treating the latter with the salt of'an alkali metal until paradiohlorbenzolsulfonate of'said metal is produced,

and re-acting on the latter with the hydroxid gfdan alkali metal to produce a hydrochinon o y.

4. In the process of making hydrochinon, the steps of reacting on paradichlorbenzol with oleum at 130 to 140 C. with vigorous" a solution of-causti'c s'oda, heating the mixture under pressure at a temperature of from 17 5 to 200"- C. to produce the'sodium salt of hydrochinon, acidifying the solution, boil-- ing, cooling, and then' extracting the hydro chlnon with a suitable solvent.

6. In the process of making hydrochinon, the step of reacting on a parad-ihalogenbenzolsulfonate with a metallic'hydroxid until the hydrochinon salt of said metal is produced, and recovering hydrochinon from the reaction mixture. I

7 In the process of making hydrochinon, I

the step of reacting on the paradichlorbenzolsulfonate of an alkali metal with the by droxid of an alkali metal until the hydro chinonsalt of-said metal is produced.

8. In the process of making hydrochinon, the step ofreacting on sodium paradichlorbenzolsulfonate with a solution of caustic soda under pressure at a temperature from 175 to 200 (3., until the sodium salt of hy- I drochinon is produced. I

9. In the process of making hydrochinon, the step'ofreacting on 100 parts of sodium paradic-hlorbenzolsulfonate with 150 sure at a temperature from 175 to 200 C., until sodium salt of hydrochinon is produced. 10. In the proeessof making hydrochinon,

"the step of reacting on sodium paradichlorbenzolsulfonate with a solution of caustic soda under pressure at a temperature from artsof caustic soda in 225 parts of water un er press 175 to 200 C., for approximately twentyfour hours.

' 11. In the'process of making hydrochinon, i

the step of reacting on the paradichlorbenzolsulfonate ofan alkali met-a1 with the hydroxid of an alkali metal until the hydrochinon salt of said metal is produced,

freeing the hydrochinon with an acid, and. extracting thereof.

12. In the process of making hydrochinon, the step of reacting on sodium paradichlorbenzolsulfonate with a solution of caustic soda under pressure at a temperature from 17 5 to 200? C., until the sodium salt of hythe hydrochinon with Ia solvent drochinon is produced, acidifying the solution, boiling, cooling, and then extracting the hydrochinon with ether.

Signed at Rochester, New

day of June, 1920. I

' HAROLD VON BRAMER.

York, this 23rd 

